About us
About Best Fire Calculator
Best Fire Calculator is a free, independent tool that helps you answer the two questions at the heart of the FIRE movement: how much do you need to retire, and when can you actually stop working? We built it because most retirement calculators flatten your whole financial life into a single number — and real life is never that simple.
Why we built it
Financial independence rarely arrives in a straight line. You spend years saving, a partner may keep working after you stop, a mortgage gets paid off, health-insurance costs spike before Medicare, and pensions or Social Security start at different ages. We wanted a calculator that models that real timeline — phase by phase — instead of assuming one flat income and one flat spending number forever. So we built one and made it free for everyone.
What makes it different
- • Every kind of FIRE — Coast, Lean, and Fat FIRE in one place, plus your core FIRE number.
- • Built for couples — give each partner their own savings, retirement age, pension, and Social Security date.
- • Tested against history — your plan is replayed through 150+ years of real market data and thousands of Monte Carlo scenarios.
- • Private by design — everything runs in your browser. No account, no tracking of your numbers.
Our promise
The calculator is, and will remain, free to use. It is an educational planning tool, not financial advice — but we work hard to keep the underlying engine accurate and grounded in the same standards the FIRE community relies on. Have a question or a feature idea? Get in touch.